The present invention relates to a conveyance system of the type with skid handling and in particular to the area of the system where the system of transfer of skids from one path to another is located.
Conveyance systems of the type termed xe2x80x98skidxe2x80x99 or xe2x80x98skid systemsxe2x80x99 used for internal handling in industrial plants are known. These systems are made up of an assemblage of various handling means such as chain or belt, chain accumulation conveyors with idling rollers, powered roller conveyors termed xe2x80x98roller tablesxe2x80x99, rotary tables, head transfers with clearance and hold tables et cetera. Load support members in the form of skids and circulating this way along the system with paths, speeds, stop and wait times which depend on the programmed cycles and are controlled by purposeful electrical control equipment rest on the handling means.
As regards the head transfers which connect transversely two connected lines arranged parallel between them they have heretofore been equipped with a plurality of release and wait tables to allow regular flow from one line to the other, allow a certain accumulation of loaded or empty skids, and keep available a certain number of free positions (free tables) to give flexibility to the operation of both the main lines.
To function, the intermediate tables have to be equipped with skid raising, lowering, stopping and alignment means and are piloted by the central system.
The end tables are also equipped with motorized rollers to allow the skid to enter and leave the transfer at a right angle.
Only in special cases can the tables be eliminated i.e. when the skid is equipped with soles broad enough to rest well on supplementary idling rollers applied to the chain and with overall dimensions of the loads conveyed less than that of the skids. Control stops are arranged on the outlet side of the conveyor to stop arriving skids and prevent their uncontrolled outlet. Suitable conditions occur only in a few cases and such a solution cannot be generalized.
It has also been proposed to divide the transfer in many members with room for a single skid. This system is limited by the relative difficulty of housing the motorization in inter-connected systems, reduction of available spaces and high costs.
If relatively short the head transfers could employ only two end tables side-by-side but they would lose the accumulation function provided by the intermediate tables and consequently their operating flexibility.
The general purpose of the present invention is to overcome the above shortcomings by supplying a skid system equipped with a transfer of advanced conception.
In view of this purpose it is sought to provide in accordance with the present invention a skid handling system comprising at least two skid conveyance lines with a transfer arranged between the two lines to pass skids from one to the other characterized in that the transfer comprises a skid conveyor with a clearance table at each end at the transfer point from and to said two conveyance lines and skids are accumulated on the conveyor between the tables.